Improvement in nickel-plating



' UNITED STATEs PATENT OFFICE.

ISAAC ADAMS, JR., OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN NICKEL-PLATING.

- Specification forming part of Letters Patent No. 154,435, dated August25, 1874; application filed October 21, 1872.

To all whom it may concern Be it known that I, IsAAo ADAMS, Jr., ofBoston, in the State of Massachusetts, have invented a new and usefulImprovement in Nickel-Plating; and I do hereby declare the following tobe a full and correct description of the same.

The nature of the metallic deposit from solutions used fornickel-plating is such'as to produce a state of tension in them, wherebythe adhesion which naturally exists between surfaces chemically clean,and exactly applied to one another, as in the galvanic deposit, ismaterially lessened. This peculiarity of nickel deposits appears toexist whether the metal is thrown down by a very weak galvanic current,or whether it is produced at the maximum rate of speed. All galvanicdeposits of nickel are crystalline, and the distribution of crystalsover the surface of the article to be plated is far from being perfectlyregular and even, the deposited metal accumulating on the edges orprominent parts of the object. The deposit, when taken from theplating-bath, is apparently somewhat in the condition of a plate ofmetal which has been hammered along the middle, the edges remainingnntoucheda process which, by producing an unequal'strain, forces thehammered plate to turn or curl upon itself. From this apparent tension,or from some such cause, there is a tendency of the electro deposits ofnickel to strip or peel up, and this tendency has been found to be sogreat when applied to plain surfaces, and when the metal is required tobe of a thickness exceeding about one two-thousandths of an inch, aspractically to limit, and in some cases preclude, its application tocertain classes of articles, more particularly cutlery and articleswhich are liable to be forcibly bent or twisted, or subjected to heavyblows or shocks.

The object of this invention is to remedy this defect; and this Iaccomplish by subjecting the plated articlesto a degree of heat, in

any suitable apparatus, s uflicient to neutralize the tension, or toallow the particles of metal to rearrange themselves in such a manner asto relieve any unequal strain there may be, from whatever cause.

A very low red heat, visible in the dark, does this to the bestadvantage, the nickel oxidizing too rapidly at a higher temperature, andthe required effect not being produced in the least at a temperatureconsiderably lower. Articles made from metals or alloys whosemelting-point is below 500 Fahrenheit cannot be treated by this method.

' This invention is not only a remedy for stripping, but by its use thetoughness and pliability of the deposited metal are enhanced. Manyarticles of steel or iron which could not otherwise be economicallyhandled may by this method be plated and polished in a semitinishedstate, and afterward formed and tempered (in the case of steel) if needbe.

It is true that by this process the deposited metal is, to some degree,softer than the original before treatment; but, on the other hand, themethod allows of a much heavier plate, and, consequently, more eflicientprotection to the metal underneath, not to mention the reduced price atwhich some articles may be finished.

Sheet brass or copper may be cut-into blanks, plated, and spun or struckup into various shapes, and even burnished, if necessary; and by thisprocess short lengths of iron, steel, or

other rod can be heavily plated, and drawn with proper precaution to aconsiderable degree of fineness.

I claim- The process or method of treating metallic articles coated withnickel by subjecting the same to heat, substantially in the manner andfor the purpose specified.

ISAAC ADAMS, J R.

Witnesses SAML. W. BATES, WILLIAM W. SWAN.

